From EP 0 466 863 B1 there is known a device for connecting a driveline in a motor vehicle with a transfer case for a plurality of drivelines. One of the drivelines is permanently connected to a drive unit and a further driveline that can be connected to the drive unit. For connecting the driveline, there is provided an electronically actuatable friction coupling which can be arranged in a transfer case or a differential drive.
In such drive assemblies with a connectable driveline, the associated driving axle is not driven permanently in order to keep any losses low. But in the disconnected condition, too, the torque transmitting components of the connectable driving axle also rotate, which leads to undesirable power losses. Such power losses are responsible for motor vehicles having multiple driven axles with a hang-on driveline comprising a higher fuel consumption than motor vehicles driven by one axle only.
What is needed is a coupling assembly for connecting a driving axle in a motor vehicle having multiple driven axles, which coupling assembly permits a reduction in undesirable drag moments and power losses and whose design is simple and cost-effective.